Provided is a multi-beam optical scanning apparatus, which is capable of reducing an inter-light-beams illuminance difference at the same image height on a surface to be scanned and forming a high-definition and high-quality image where no unevenness in density of image exists, and an image forming apparatus using the multi-beam optical scanning apparatus.In the multi-beam optical scanning apparatus that brings a plurality of light beams emitted from the plurality of light emission portions into incident on the deflecting surface of the light deflector so as to exceed a width in a main scanning direction of the deflecting surface, when performing the emission light amount control for each of the plurality of light emission portions so that illuminances of the plurality of light beams become same at every image height on the surface to be scanned, the control means changes emission light amounts of the plurality of light emission portions at a maximum scanning angle, thereby reducing the inter-light-beams illuminance difference on the surface to be scanned.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A multi-beam optical scanning apparatus comprising: light source means including a plurality of light emission portions; a light deflector including a deflecting surface; an incident optical system in which a plurality of light beams emitted from the plurality of light emission portions is made incident on the deflecting surface of the light deflector with a width in a main scanning direction wider than that of the deflecting surface; an imaging optical system that images the plurality of light beams reflected by the light deflector on a surface to be scanned; and control means for independently controlling emission light amount of each of the plurality of light emission portions, wherein when the emission light amount of each of the plurality of light emission portions is controlled so that illuminances of the plurality of light beams become same at every image height on the surface to be scanned, the control means controls emission light amounts of the plurality of light emission portions at a maximum scanning angle so as to be different from one another.
2. A multi-beam optical scanning apparatus according to claim 1 , wherein when the emission light amount of each of the plurality of light emission portions is controlled so that illuminances of the plurality of light beams become same at every image height on the surface to be scanned, the control means controls emission light amounts of the plurality of light emission portions at a same scanning angle in a partial region of a whole scanning angle region so as to be different from one another.
3. A multi-beam optical scanning apparatus according to claim 1 , wherein the control means controls the emission light amount of each of the plurality of light emission portions so that illuminances of the plurality of light beams on the surface to be scanned are linearly-changed in accordance with the image height.
4. A multi-beam optical scanning apparatus according to claim 1 , wherein the control means controls the emission light amount of each of the plurality of light emission portions so that illuminances of the plurality of light beams on the surface to be scanned are non-linearly changed in accordance with the image height.
5. A multi-beam optical scanning apparatus according to claim 1 , further comprising: an illuminance distribution compensating optical element provided in an optical path between the light source means and the surface to be scanned and for correcting an illuminance distribution in one scanning line on the surface to be scanned, wherein the illuminance distribution compensating optical element corrects an illuminance of the scanning line on the surface to be scanned so as to increase in the main scanning direction from a center portion to end portions.
6. A multi-beam optical scanning apparatus according to claim 1 , further comprising: adjusting means for adjusting each position at which a light intensity of the respective light beams emitted from the plurality of light emission portions in a main scanning section becomes maximum on the deflecting surface of the light deflector, wherein the adjusting means adjusts so that a position, at which the light intensity of the light beam emitted from the plurality of light emission portions in the main scanning section is maximum on the deflecting surface, and a center position of an effective scanning range in the main scanning section on the surface to be scanned coincide with each other.
7. A multi-beam optical scanning apparatus according to claim 1 , further comprising: adjusting means for adjusting each position at which a light intensity of the respective light beams emitted from the plurality of light emission portions in a main scanning section becomes maximum on the deflecting surface of the light deflector, wherein the adjusting means adjusts so that a position, at which the light intensity of the light beam emitted from at least one light emission portion among the plurality of light emission portions in the main scanning section becomes maximum on the deflecting surfaces and a center position of an effective scanning range in the main scanning section on the surface to be scanned coincide with each other.
8. A multi-beam optical scanning apparatus according to claim 1 , wherein the plurality of light emission portions are spaced apart from one another in the main scanning direction and the sub-scanning direction.
9. A multi-beam optical scanning apparatus according to claim 1 , wherein the plurality of light emission portions are spaced apart from one another in the sub-scanning direction.
10. An image forming apparatus comprising: the multi-beam optical scanning apparatus according to claim 1 ; a photosensitive member disposed in front of the surface to be scanned; a developing device for developing an electrostatic latent image formed on the photosensitive member by a light beam with which scanning is performed by the multi-beam optical scanning apparatus as a toner image; a transferring device for transferring the developed toner image to a material to be transferred; and a fixing device for fixing the transferred toner image to the material to be transferred.
11. An image forming apparatus comprising: the multi-beam optical scanning apparatus according to claim 10 ; and a printer controller for converting code data inputted from an external device into an image signal and inputting the image signal into the multi-beam optical scanning apparatus.
12. A color image forming apparatus comprising: a plurality of multi-beam optical scanning apparatuses according to claim 1 ; and a plurality of image bearing members for forming images in mutually different colors, each of the plurality of image bearing members disposed on the respective surfaces to be scanned of the plurality of multi-beam optical scanning apparatuses.
13. A color image forming apparatus according to claim 12 , further comprising: a printer controller for converting color signals inputted from an external device into image data for different colors and inputting the image data into the respective multi-beam optical scanning apparatuses.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
May 27, 2005
September 18, 2007
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